improve flexibility in Orchestra\Html\HtmlBuilder

Its more flexibility & easy this way.
---

No more:
```php
echo HTML::link('foo', HTML::raw(HTML::image('bar', 'bar')));
```
Just:
```php
echo HTML::link('foo', HTML::image('bar', 'bar'));
```

And if the user want to show the tag as content he can do this:
```php
echo e(HTML::image('bar', 'bar')->get());
```
Or:
```php
echo e( (string) HTML::image('bar', 'bar'));
```
Sorry about my pure English.